make repairs cost at least as much as 1% to avoid spam

MANUAL.html

@@ -147,7 +147,8 @@
   property). It is therefore in the player's interest to ensure buildings are repaired in time, and to
   keep enough balance to meet land tax requirements. Repairing a building costs labour and materials.
   If a building's repair level falls below 70%, its efficiency starts decreasing. Above 70%, no ill
-  effects apply.
+  effects apply. To disincentivize constant repair spam, repairing a building in 99% condition or
+  better costs as much as repairing it from 99%.
   <br>
   Some building types have restrictions on size, depending on economic power. This should be kept in
   mind when buying land. The following table lists the minimum size of a plot for building types. The

src/cc/cc.cpp

@@ -987,6 +987,7 @@ void get_repair_costs(uint32_t x0, uint32_t y0, uint32_t x1, uint32_t y1, uint8_
   costs.clear();
   if (delta_repair == 0)
     return;
+  delta_repair = std::max<uint32_t>(delta_repair, MIN_DELTA_REPAIR);
   std::map<uint32_t, uint32_t> budget;
   if (!get_build_settings_requirements(x0, y0, x1, y1, role, 100, budget))
     return;

src/cc/cc_config.h

@@ -49,6 +49,7 @@
 #define MAX_MATCHES_PER_TRADE 256
 #define LAND_TAX_PER_TILE ((uint64_t)2000)
 #define DEFAULT_REPAIR 1000000
+#define MIN_DELTA_REPAIR 10000
 #define INACTIVE_DECAY_PERCENTAGE 120
 #define NO_MILITARY_DECAY_MULTIPLIER 150
 #define MAYOR_PAYOUT 1/1000